Integrated thermoelectric module

ABSTRACT

The integrated thermoelectric module is formed of a set of thermoelectric elements, consisting of N type and P type conductor and/or semiconductor elements electrically connected in series and/or in parallel and thermally connected in parallel and assembled on flexible supports ( 11 ) of polymeric material, capable of electrically isolating said circuit, but having a high thermal conductivity efficiency. Each support ( 11 ) is connected to a heat exchanger ( 12 ) by means of connection materials ( 13 ) having low thermal impedance allowing optimum connection even at low adhesion pressures. The thermoelectric elements are distributed in its interior part so as to geometrically harmonize heat transferred from the integrated thermoelectric module with heat exchanged by the heat exchangers, thus making the temperature distribution on said exchangers as uniform as possible.

TECHNICAL FIELD

The present invention generally refers to the field of solid-statethermoelectric devices using the Peltier effect to cool and/or heatcivil and/or industrial environments.

PRIOR ART

The thermoelectric devices of the abovementioned type have been known inthe art for quite some time and generally comprise a thermoelectricmodule or thermopile consisting of a set of thermoelectric elementswhich, in their turn, are formed by P type and N type conductor and/orsemiconductor elements electrically connected in series and thermallyconnected in parallel, wherein the thermoelectric elements are usuallyelectrically connected in series and thermally connected in parallel andare assembled on supports made of electrically insulating, but thermallyconductive, material and generally made of stiff ceramic material. Thesethermoelectric modules must then be connected to heat exchangers inorder to form heat pumps for household and industrial appliances.

The thermoelectric modules known in the art generally present somedrawbacks related to their thermal efficiency and fragility. As to thefirst of these drawbacks, in particular, the thermoelectric modulesknown in the art do not allow to achieve a uniform temperaturedistribution on the heat exchangers to which they are connected, becausethey cannot be adapted to the variable characteristics of the heatexchangers depending on the type of application they are intended for.As to the second drawback, it is known that, because of the fragility ofthe support, during the assembly steps with the heat exchangers rupturesfrequently occur due to the high contact pressures required for goodfunctioning and/or during operation due to the different thermalexpansions of the two faces of the module, caused by the differenttemperatures of the heat exchangers they are connected to.

DISCLOSURE OF THE INVENTION

The present invention pursues the object to overcome said drawbacks ofthe thermoelectric modules known in the art by providing a newlydesigned thermoelectric module that is to be assembled and integratedwith heat exchangers in order to form a thermoelectric heat pump.

According to the present invention, this object is achieved by aintegrated thermoelectric module formed of a set of thermoelectricelements, each of which is made of P type and N type conductor and/orsemiconductor elements electrically connected in series and thermallyconnected in parallel, wherein said thermoelectric elements areelectrically connected in series and/or in parallel and thermallyconnected in parallel and are assembled on flexible supports made of apolymeric material capable of electrically insulating the circuit, buthaving a high thermal conductivity performance. Said supports, one beingon the hot side and the other on the cold side of the thermoelectricmodule, are connected to their respective heat exchangers by means ofconnecting materials having low thermal impedance, for instance of phaseconversion type or graphite-base type, allowing optimum connection evenat low adhesion pressures. Said integrated module is characterized inthat the thermoelectric elements are distributed in its interior so asto geometrically harmonize heat transferred from the integratedthermoelectric module with heat exchanged by the heat exchangers, thusmaking the temperature distribution on said heat exchangers as uniformas possible, in order to maximize the efficiency of the integratedthermoelectric module by reducing the thermal head between its twofaces.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described as a non-limiting examplewith reference to the figures of the accompanying drawings, in which:

FIG. 1 is a sectional view of the integrated thermoelectric moduleaccording to the invention, associated with heat exchangers of planarform in order to form a thermoelectric heat pump;

FIG. 2 is a sectional view of the integrated thermoelectric moduleaccording to the invention, associated with heat exchangers of concaveand/or convex form in order to form a thermoelectric heat pump;

FIG. 3 is a sectional view of the integrated thermoelectric moduleaccording to the invention, associated with heat exchangers ofcylindrical form with a polygonal cross section in order to form athermoelectric heat pump; and

FIG. 4 is a sectional view of the integrated thermoelectric moduleaccording to the invention, associated with heat exchangers ofcylindrical form with circular cross section in order to form athermoelectric heat pump.

BEST MODE OF CARRYING OUT THE INVENTION

Referring to FIG. 1 of the drawings, the integrated thermoelectricmodule 10 is formed of a set of thermoelectric elements, as describedabove, assembled on flexible supports 11 haying the form of a thinmembrane or film of polymeric material. The thermoelectric elements areuniformly or non-uniformly distributed on the flexible support 11depending on the particular use the thermoelectric module 10 is intendedfor.

The peripheral shape of the integrated thermoelectric module may bedifferent and may be rectangular, for instance even square, orcurvilinear, for instance circular.

The polymeric material of the flexible support 11 is preferably made ofa polyimide, commercially available under the trade name Kapton®.

The integrated thermoelectric module 10, thus formed, is associated withheat exchangers 12 and is caused to adhere to the base surfaces of thelatter, preferably by means of a thermo conductive material 13 of phaseconversion type. Instead of the thermo conductive material of phaseconversion type, a graphite material may be used as connecting material,laid on one side only or on both sides of the integrated thermoelectricmodule 10.

The base surfaces of the heat exchangers may be planar, as shown in FIG.1, or concave and/or convex, as shown in FIG. 2, or cylindrical with apolygonal cross section, as shown in FIG. 3, or cylindrical withcircular cross section, as shown in FIG. 4. Heat exchangers 12 may betouched by gaseous or liquid fluids as well as by fluids undergoingphase conversion. In addition, the surfaces being touched may beprovided with fins. The heat exchangers 12 may be made of metal ornon-metal material. For instance, as non-metal material, a graphitematerial may be used.

The connecting materials used to connect the integrated thermoelectricmodule 10 to the heat exchangers 12 may be either distributed in asubstantially uniform way on the flexible support 11 or they may belocalized on the flexible support 11 in correspondence with thethermoelectric elements.

The technical advantages achieved with a thermoelectric device accordingto the invention are as follows.

With a proper distribution of the thermoelectric elements inside theintegrated thermoelectric module 10, it is possible to harmonize theconfiguration of said module with that of the heat exchangers 12 inorder to improve the correspondence between heat transferred from themodule and heat exchanged by the heat exchangers 12 and to achieve atemperature distribution as uniform as possible, thus improvingefficiency of the integrated thermoelectric module 10 with reduction ofthe thermal head between its two faces.

INDUSTRIAL APPLICABILITY

The use of a connecting material between integrated thermoelectricmodule 10 and heat exchangers 12, as described, permits to obtain astable connection even in the absence of an excessive contact pressurein order to achieve close contact between integrated thermoelectricmodule and heat exchangers. In addition, said connecting materials havehigh thermal conductivity and are capable of absorbing, in the bestpossible manner and without damages to the module itself, possiblethickness irregularities of the module due to different height of thethermoelectric elements and differential effects in terms of thermalexpansion of the heat exchangers, when, during operation, they findthemselves at mutually different temperatures. Finally, if heatexchangers are used having non-planar adhesion surfaces, said connectingmaterials could be used to offset non-conformity of the planar base ofthe thermoelectric elements with the curvature of the exchanger base, byfilling up the interstices that are present between flexible support 11and surface of heat exchangers 12.

1. Integrated thermoelectric module (10) formed of a set ofthermoelectric elements, each of which is made of P type and N typeconductor and/or semiconductor elements electrically connected in seriesand thermally connected in parallel, wherein said thermoelectricelements are electrically connected in series and/or in parallel andthermally connected in parallel and are assembled on flexible supports(11) made of a polymeric material, connected to the respective heatexchangers (12), characterized in that the thermoelectric elements aredistributed in the interior of the integrated thermoelectric module (10)so as to geometrically harmonize heat transferred from the integratedthermoelectric module (10) with heat exchanged by the heat exchangers(12) thus making the temperature distribution on said heat exchangers(12) as uniform as possible, in order to maximize the efficiency of theintegrated thermoelectric module (10) by reducing the thermal headbetween its two opposite faces.
 2. Integrated thermoelectric moduleaccording to claim 1, characterized in that in order to connect saidmodule (10) to heat exchangers, (12) a thermally conductive material ofphase conversion type (13) is used having high thermal conductivity andcapable of absorbing without damages possible irregularities of thethickness of the integrated thermoelectric module (10) due to heighttolerances of the thermoelectric elements.
 3. Integrated thermoelectricmodule according to claim 1, characterized in that in order to connectsaid module (10) to heat exchangers (12) a thermally conductive graphitematerial is used, laid either on one face only or on both faces of theintegrated thermoelectric module (10).
 4. Integrated thermoelectricmodule according to claim 1, characterized in that its base has arectangular shape, for instance a square shape.
 5. Integratedthermoelectric module according to claim 1, characterized in that itsbase has a curvilinear peripheral shape, for instance a circular shape.6. Integrated thermoelectric module according to claim 1, characterizedin that the thermoelectric elements are uniformly distributed inside theintegrated thermoelectric module (10).
 7. Integrated thermoelectricmodule according to claim 1, characterized in that the thermoelectricelements are non-uniformly distributed inside the integratedthermoelectric module (10).
 8. Integrated thermoelectric moduleaccording to claim 1, characterized in that said module is associatedwith heat exchangers having a planar connection surface.
 9. Integratedthermoelectric module according to claim 1, characterized in that saidmodule is associated with heat exchangers having a concave and/of convexconnection surface.
 10. Integrated thermoelectric module according toclaim 1, characterized in that said module is associated with heatexchangers having a cylindrical shape with polygonal cross section. 11.Integrated thermoelectric module according to claim 1, characterized inthat said module is associated with heat exchangers having a cylindricalshape with a circular cross section.
 12. Integrated thermoelectricmodule according to claim 1, characterized in that the heat exchangersare finned.
 13. Integrated thermoelectric module according to claim 1,characterized in that the heat exchangers may be touched by gaseous orliquid fluids as well as by fluids that are bound to phase conversion.14. Integrated thermoelectric module according to claim 1, characterizedin that the heat exchangers may be touched by fluids bound to phaseconversion.
 15. Integrated thermoelectric module according to claim 1,characterized in that the heat exchangers avail themselves of the latentheat of phase conversion of a fluid.